After a knee replacement, most people do a short set of home exercises two to three times a day.
The first two weeks are about getting the knee STRAIGHT and switching the thigh muscle back on. Weeks 2 to 6 are about winning back bend. Weeks 6 to 12 are about strength and balance.
Each session takes about 20 to 30 minutes. You don’t need equipment beyond a bed, a chair, a towel and a step.
Some discomfort during exercise is expected. The rule of thumb: it should settle within an hour or two, and the knee should not be MORE swollen or sore the next morning.
Your surgeon or physio may give you a different program. Use theirs. What follows is the usual shape of it.
The first two weeks: straight knee, working thigh
- Ankle pumps: point your foot down, then pull it up, rhythmically for 2 to 3 minutes, two to three times an hour while you’re awake. This keeps blood moving in the calf and helps with swelling
- Thigh squeezes (quad sets): lying down, tighten the front of your thigh and push the back of your knee toward the bed. Hold 5 to 10 seconds. About 10 in a row, rest, repeat
- Straight leg raises: tighten the thigh first, then lift the whole leg a few inches off the bed. Hold 5 to 10 seconds and lower slowly. If the knee sags as you lift, do more thigh squeezes and come back to this
- Heel prop: a rolled towel under your ankle, nothing under the knee. Let the knee sink toward straight for a few minutes at a time, several times a day. This one is the most skipped and the most important
- Heel slides: lying on your back, slide your heel toward your bottom until you feel a firm stretch, hold 5 to 10 seconds, slide back. A towel or plastic bag under the heel helps it glide
- Walking: short, frequent walks with your walker or crutches. Several short walks a day beat one long one
See knee replacement recovery week by week for what the rest of recovery looks like around these exercises.
Weeks 2 to 6: win the bend
Keep the heel prop and thigh squeezes going. Add:
- Seated knee bends: sit in a firm chair, slide your foot back under the seat as far as it goes, hold 5 to 10 seconds. Use your other foot to nudge it a little further
- Sit to stand: stand up from a firm chair without using your hands if you can, and sit down slowly. Start with 5 to 10. A higher chair or a cushion makes it easier at first
- Standing knee bends: holding a counter, bend the knee to lift your heel toward your bottom, hold, lower
- Calf raises: holding a counter, rise onto your toes and lower slowly
- Stationary bike: set the seat high so your knee is almost straight at the bottom of the pedal stroke. Rock back and forth until the pedal goes all the way over. Start with a few minutes and build to 10 to 15 minutes, twice a day
- Longer walks: most people move from a walker to one crutch or a cane around weeks 2 to 3, once they can walk and stand for more than about 10 minutes
If your bend is stuck, the detail matters. See stiff knee after knee replacement.
The exercises are small. Doing them every day is the big part.
Weeks 6 to 12: build strength and balance
By now you are usually walking without an aid on flat ground. The exercises shift from movement to strength.
- Step-ups: step up with the operated leg, bring the other foot up, step down. Hold a rail. Start with a low step, such as the bottom stair
- Step-downs: stand on the step and slowly lower the other heel to the floor, then straighten back up. This is harder than it looks and very useful for stairs
- Mini squats: feet shoulder-width apart, holding a counter, bend both knees a short way as if sitting back into a chair. Keep it shallow at first
- Balance: stand on the operated leg while holding the counter lightly. Aim for 30 seconds. Then try it with one fingertip, then none
- Bike with resistance: gradually longer and harder, building toward 20 to 30 minutes
- Walking outdoors: slopes, grass and uneven ground, a little further each week
Strength keeps coming back well past three months. Keep some of this work going after formal therapy ends, two or three times a week, for the rest of the first year.
How much pain is OK?
- During the exercise: a firm stretch or a moderate ache is fine. Sharp, stabbing pain is a signal to ease off
- After the exercise: discomfort should settle within an hour or two
- The next morning: this is the real test. If the knee is hotter, more swollen or more painful than the morning before, you did too much. Ease back for a day, don’t stop
- Time your pain relief: take it as prescribed so it is working when you exercise, not wearing off halfway through
- Ice after exercise can take the edge off. See swelling after knee replacement for how to use it properly
What to avoid
- A pillow under the knee in bed. It feels good and trains the knee to stay bent
- One big session instead of several small ones. Knees respond better to little and often
- Twisting and pivoting on the operated leg in the early weeks. Turn with small steps
- Running and jumping. Most surgeons discourage them. Walking, cycling, swimming and golf are the usual long-term choices
- Deep squats with weight in the first three months
- Pushing through sharp pain to hit a number. A few degrees a week is normal progress
The American Academy of Orthopaedic Surgeons has illustrated instructions for the standard exercises if you want pictures to follow.
Call your surgeon today if
- Your calf is painful, tender or newly swollen: possible clot in the leg
- You are suddenly short of breath or have chest pain: call emergency services. A clot can travel to the lung
- The wound is red, spreading, weeping or draining
- You have a fever or chills
- The knee is getting MORE painful, not less, at rest as well as with activity
- You felt a pop or clunk during exercise and now can’t bend, straighten or put weight on the leg
Mention it at your next review if
- The knee still won’t go fully straight at six weeks
- Bending has stopped improving for a couple of weeks
- You still can’t do a straight leg raise without the knee sagging
- Pain is stopping you from doing your exercises
Straight first, bend second, strength for the rest of the year.